Described herein are methods of controlling gloss of an image using a UV curable overcoat, including applying heat to the overcoat following application but prior to UV curing of the overcoat. The UV curable overcoat includes a gellant and a curable wax component.
The UV curable overcoat method provides several advantages, including providing image permanence to an underlying image, and simultaneously permitting the gloss of the image to be controlled by the use of heat prior to UV curing, and optionally also by the amount of curable wax in the overcoat composition and/or the amount of overcoat composition applied to a substrate. Other advantages will be apparent from the description herein.
As digital color production printers continue to enter commercial printing markets, image permanence and document offset in images formed with such printers are issues that are being researched for continued improvement. A typical approach to attempting to improve image permanence and document offset is to apply an overcoat or overprint varnish. A variety of overcoat compositions are known, including oil-based compositions, aqueous-based compositions, and the like. For digital color production printers, it may be desirable to utilize an overcoat that may be applied in a digital fashion, for example via ink jet.
Besides image permanence and document offset, an overcoat composition may also affect gloss of the image. Often, an overcoat composition can adversely affect the gloss, for example by altering the gloss from a desired gloss for the image, typically making the image have a more matte appearance.
What is desired is a UV curable overcoat, capable of being digitally applied, that can be used to provide not only image permanence, but also to provide control over the gloss of the image.